Turbine oil



Patented ct. 356, 145

rain

BENE OH Paul W. Fischer, Long Beach, and Vance N. Jenkins, Palos Verdes Estates, Califl, assignors to Union Oil Company of California, Los

Angeles, Calif., a corporation of California No Drawing. Application January 4, 1943,

Serial No. 471,274

14 Claims.

- tended to other materials apt to be contaminated with water and to water-containing materials in which mineral oil fractions may be incorporated, such as lubricating oil fractions used in various emulsifiable oils, cutting oils, wetting agents, ex-

treme pressure oils, soluble oils, greases, and the like. Also, the improvement may be applied to any form of mineral oil, such as fuels or lubricating oils for internal combustion engines, where contact with water is likely to occur.

The principal object of the invention is to produce an oil having anti-corrosion characteristics of the indicated nature without having objectionable tendencies to emulslfy with water. This is accomplished by the inclusion in the oil of an extremely small percentage of one or more additive materials.

Briefly, the invention comprises a petroleum oil fraction suitable for any selected purpose, such as turbine lubrication, containin a very minor proportion of certain oil-soluble imidics as herein defined, containing the =NH group. The oil may or may not contain certain other indicated additives which cooperate with the imidics to give unexpectedly improved results. In the case of a turbine oil the percentage of imidic will be in the order of perhaps 0.001% to 0.1%. Greater proportions may be added if occasion demands, but commonly greater proportions do not yield materially greater benefits and, furthermore, higher concentrations tend to interfere with the emulsifying characteristics required of a turbine oil. These materials impart unusually high resistance to corrosion of metals, e. g., iron, in the presence of water, and in the indicated effective proportions do not interfere substantially with non-emulsifying characteristics required.

Also, the invention is related to methods of producing these imidic materials, because of the fact that their chemical constitution is not certain and they may be mixturesof related materials. Therefore, the invention resides also in petroleum oil containing imidics believed to have the form of the imido-esters herein described.

that is, oils containing imidic-type materials produced by the methods described for producing what are believed to be imido-esters, which materials have low melting point and predominantly are normally liquid, are oil-soluble, and are obtained by reacting suitable carboxylic acid esters, such as fatty acid glycerides and the like, with ammonia and segregating the said oil-soluble normally liquidlor low melting pointmaterial from the other reaction products as by crystallization or selective solvent extractio 1 In particular, the invention applies to the mentioned materials believed to be imido-esters and believed also to have a structural formula of the following character:

where R1 and R2 represent hydrocarbon groups which may or may not be the same. However, each of the groups R1 and R2 should contain more than two' carbon atoms and apparently should total at least about twenty in order to impart to the product sufficient solubility in the base oil being used. It is also desirable, and apparently preferable, that both R1 and R2 contain at least one olefinl'c linkage, i. e. a double bond. In addition to considering the above indicated imidic material as an imido-ester, it may also be viewed as an imido-ether. These materials are not only oil-soluble, but are predominantly normally liquid and tend to be water-soluble.

In addition to the I imido-esters above mentioned, the invention also extends to other imidics believed to be imides and amidines which are normally liquid and are oil-soluble, and tend to be water-soluble or toact as a common solvent. The additional materials are effective for the stated purposes. All of these materials are properly classifiable as imidics along with the imidoesters, because all of them contain the characterizing =NH group. Thus, imides have the following probably structural formula:

and amidine probably have the structural formula So far as is known, all oil-soluble, normally liquid materials believed to be imides and amidlnes producible by the methods herein given, as well as the imido-esters mentioned, are operative, and all are collectively included by this definition within applicants term imidics which requires that they shall also tend to be water-soluble or act as a common solvent, at least to some extent.

Imz'd0-esters.For the preparation of the imido-esters, any suitable carboxylic acid ester apparently is satisfactory as a starting material; for example, any fatty oil, that is, the glyceride of any fatty acid, having a suflicient number of carbons to meet the above indicated preference of about twenty carbons per molecule. Suitable feed stocks are the normally liquid fats such as cottonseed oil, corn oil, fish oils and. the like.

In preparing these imido-esters, the esters or glycerides are reacted with an excess of ammonia at temperatures within the range of about 40 C. to 400 C., preferably between about 100 C. and about 200 C. (e. g. 125 0.), and under any pressure from atmospheric up to about 2000 lbs. gage, e. g. at atmospheric or at 700 lbs. A reaction time between 30 minutes and 60 hours may be employed (e. g. 5 hours), and oxygen or air should be excluded from the reaction vessel as by means of an inert gas such asv nitrogen or natural gas. Catalysts such as silica gel may be used if desired. The product thus obtained contains about 25% of the desired normally liquid imidic believed to be the imido-ester. However, a more desirable product is obtained by heating the above resultant product in the same reaction vessel at about 100 C. after removing and excluding ammonia from the vessel. This heating operation may be conducted for between and 50 hours, ordinarily about 24 hours. The reaction product of this continued heating contains about 70% of the desirable normally liquid materials as against 25% thereof obtained from the ammonia treating Process.

The non-liquid portions of the two products mentioned are largely the normally solid amides 01' the type represented by the formula These amides, besides being normally solid, are oil-insoluble and also possess relatively low value as anti-corrosion agents. To exclude these normally solid and valueless materials, the crude product is treated for separation of the liquids from the solids by crystallization, or by fractional crystallization or by selective solvent extraction with solvents for the "imidic such as light naph- 1 tha, acetone and dioxane. cedure is to mix the crude reaction product with liquid pentane, or acetone whereby the imidics are selectively dissolved from the amides and other valueless materials, and are removed therefrom in the solution and from which they may be separated by evaporation. These materials are oilsoluble, and constitute imidics of this invention. However, they sometimes contain a very small proportion of low melting point materials (about 36 C. M. P.) which are however, solidat normal temperatures, and the latter, which are less valuable may be removed from the preferred normally liquid fractions by selective solvent extraction as with acetone in regulated proportions, or by crystallization. These normally liquid fractions are believed to be imido-esters and are preferred to the liquid fractions containing also the small proportion of low melting point materials, especially One desirable pro- I where the 011 containing this additive material is to be used at temperatures below about 20 C.

Certain commercially available amides have been found to contain appreciable although minor proportions of amidics or imido-esters of this invention. These also may be recovered by selective solvent extraction or crystallization as just indicated. In all instances the desired amidics have lower boiling points than the amides, and it is possible to separate them by fractional distillation, preferably under vacuum.

, As a specific example of the preparation of the imido-esters above mentioned, 200 grams of cottonseed oil are reacted with liquid ammonia (NI-I3) in excess (e. g. at a weight ratio of about one part of ammonia to three part of the oil), in a pressure chamber at about 750 lbs. gage and heating the batch to a temperature of about C. with agitation for a reaction period or about five hours. At this time the reaction product contains about 25% (more or less) of the desired normally liquid imido-ester. In order to increase the percentage of the imido-ester, the ammonia supply is cut oil, residual ammonia is removed from the reaction chamber and air is excluded as by introducing natural gas, and the product is further heated at a temperature in the order of C. at substantially the same pressure as previously used and for a period of about 24 hours. At this time'the content of the normally liquid imido-esters has increased materially, for example to about 75% of the batch. The reaction product is then fractionated, first by cooling to room temperature, and then washing out the oil-soluble materials as with liquid propane or light petroleum naphtha. The solution contains the normally liquid imido-esters and a small proportion of other oil-soluble material which, however, are normally solid but have low melting points in the order of 36 C. to 40 C. By cooling the solutionof the imidics to a temperature of about 0 C., the less desirable normally solid, low melting point substances crystallize out and may be removed from the liquid as by filtration. Such separation may also be effected by selective solvent extraction as with acetone.

Imido-esters (imido-ethers) of the indicated nature may also be prepared 'by'the reaction of a suitable amide with a suitable alcohol, such as glycerol, octyl alcohol and the like. For example, oleic amide may be reacted with glycerin as the alcohol and inthe presence of ammonia. The oleicamide may be produced in any of the known methods by reacting oleic acid with ammonia such as by the methods above described for reacting fatty oils with ammonia. of the amide with the glycerol in the presence of ammonia is carried on at temperatures and pressures as heretofore indicated, for example at elevated temperatures up to about 400 C. -(e. 'g. 125 C.) and pressures from atmospheric up to about 2000 lbs. (e. 8. about 700 lbs. gage) for a suitable time to produce the desired amount of product, for example, six hours, or other time up to perhaps as high as 48 hours. Under reaction with the indicated conditions for about six hours, about 30% of the resultant product comprises the normally liquid oil-soluble imidoesters with a limited amount of the low melting point oil-soluble imido-esters previously mentioned as produced by the other processes. Here again, the proportion of the desired normally liquid product may beincreased by further heating the reaction products in the absence of am-- monia and air at a somewhat higher temperature The reaction emulsion problems.

preferably about 180 C., or between about 50 C. and about 300 C. Here, also, the amount of the normally liquid products is increased to the order of about 70% of the total reaction products, and these liquid products may be separated below, which are believed to be imides and amidines and presumed to have the structural formulas heretofore indicated. So far as is known, all of the imides and amidines, as well as imidoesters, containing a total of about carbons or more per molecule, whereby good oil-solubility is imparted, are useable.

For example, the relatively oil-soluble, normally liquid materials which are believed to be imides and have the formula R,-c=o

where R1 and R2 may be the same or different organic radicals totaling the above-indicated number of carbons, may be produced by reacting a fatty acid amide with a fatty acid chloride. Such amides and chlorides may be produced by such methods as described in Reppe Patent 2,013,108 as to the amide, and in the Ralston Patent 2,262,431 as to the acid chloride.

Specifically, oleic imide was prepared by heating 31 g. of the oleic amide (made as above indicated) with 31 g. of the oleic acid chloride in an atmosphere of natural gas at a temperature of about 140 C. and atmospheric pressure for a period of about 8 hours. By treatment of the crude product with about two volumes of a commercial hexane fraction, it was separated into a hexane-insoluble fraction which was largely unchanged amide, and a hexane-soluble fraction which was largely the desired liquid imide. Ac-

tual yields from both fractions were approximately 12% amide (insoluble), 26% of a fraction which appeared to be largely oleic acid or oleic anhydride (from both the soluble and insoluble fractions), and 62% imide (soluble).

Also, the sulfur analogs of the above imidics, which contain one or more S atoms each replacing an O atom, and prepared by the above methods from the corresponding thio" reactants, are also efiective anti-corrosion agents, and may be used as described below for the oxygen-containing imidics.

Final anti-corrosion oil product To produce the non-corrosive, relatively nonemulsifying turbine oils of this invention, the imidics prepared by the methods described above are added to a suitable base oil such as the one described below in proportions of about 0.001% to 0.1% by weight. Even smaller proportions such as, perhaps 0.0005% might be used with some corresponding benefit. Again, larger proportions such as about 0.2% may be used although, commonly, these greater amounts do not offer any up to about 10% or more may be desirable in other compositions, such as some in which they are used as wetting agents. Similar anti-corrosion effects are obtained when corresponding percentages of the described imidics are added to other petroleum fractions which are employed in the presence of water and where metal corrosion might result. This includes the well known cutting oils and other so-called soluble oils or emulsifiable oils, and rust-preventin compositions. In general, the imidics may be introduced into any oil fraction as insurance against corrosion of metals with which the oils come into contact. For example. the material may be employed in lubricating oils, especially those which have an additional function of acting as corrosion preventives during the shipping and storing of internal combustion engines whose working surfaces are to be protected against corrosive influences of moisture, air, fluids containing chemicals, and the like. It may also be possible to use the described imidics in approximately the indicated small proportions in lubricating oils and possibly in fuels for internal combustion engines especially where additives employed in the lubricating oils to overcome deposition of objectionable materials tend to cause corrosion of sensitive alloy bearings and the like. Another use is as an anti-corrosion agent in hydraulic oils, which may contain non-hydrocarbon fractions such as glycols, ethers, esters, etc.

Petroleum fractions to which the indicated small proportions of the described imidics are to be added, may be of any type according to the use intended, that is, they may be of naphthenic or parafiinic base type. Commonly, Well refined, highly paraffinic materials are employed, particularly those of lubricating viscosities, i. e. above about 150 seconds Saybolt Universal at 130 F. In connection with turbine oils this is ordinarily a necessity in order to present the commercially required high non-emulsifying characteristics.

As an example of a suitable turbine oil of this invention, a well refined SAE 20 lubricating oil was obtained which had been prepared b successively propane deasphalting and dewaxing, phenol solvent extracting, and clay treating a suitable vacuum distillate from a California crude oil. This product was used as a base oil, and 0.08% of imidics of the imide-ester type extracted from a commercial spermamide as described above was added. The resulting product substantial further improvement and often cause However, larger amounts had the following characteristics:

Saybolt Universal viscosity at F., 191 seconds; Viscosity index, 91;

Flash 460 F. C. O. C.; pour point 20 0.; Surface tension 35.6 dynes;

Interfacial tension with water, 2.5 dynes; Gravity, 295 A. P. I. at 60 F.;

Conradson carbon residue 0.007%.

The low interfacial tension with water is characteristic of imidic-containing products. A similar product was made using the lmido-esters produced from glycerides (cottonseed oil) and ammonia.

In cases where it is essential to avoid all tendency toward emulsification, we have found that octyl alcohol and some other higher alcohols such as decyl and lauryl alcohols, added in proportions in the order of 1%, e. g. from about 0.5% to perhaps 2%, will prevent emulsification. Such alcohols are oil-soluble, and have boiling points above C. or in the order of 200 C. However, these alcohols themselves tend to cause corrosion in the presence of water. We have found, however, that about 0.1% of an unsaturated (normally liquid) fatty acid such as oleic acid or the heavy metal soaps of the above fatty acids (e. g. lead soaps of tall oil) will prevent such tendencies on the part of the alcohol. Also, heavy metal soaps of the fatty acids, such as lead, iron and copper soaps, will control the corrosive tendency of the alcohol. Tall oil and its soaps are included in this category. Also, some resinous soaps such as the calcium or other metal soap of the formaldehyde-alkylated phenol condensation product of the Wilson Patent 2,250,188 (where the phenolic characteristic no longer exists) may be used.

As an example, an oil containing in the order of 0.08% to 0.1% of the imidic, around 1% of octyl alcohol, as above indicated, and around 0.1% (or between about 0.05% and 0.2%) of Oleic acid, protects metals in the presence of water from corrosion both within the liquid and at the surface, and overoomes all emulsification tendencies.

Other modifications will be apparent to those skilled in the art and are within the scope of the claims.

We claim:

1. An anti-corrosion composition comp-risinga mineral oil fraction of lubricating viscosity containing a minor proportion of oil-soluble imidoesters free from amides and other oil-soluble ammonia. derivatives, the imido ester being of the where R1 and R: represent the same or different aliphatic hydrocarbon radicals.

2. An anti-corrosion, emulsion-resistant turbine oil comprising a well refined mineral oil fraction containing about 0.0005% to about 0.1% of oil-soluble imido-ester free from amides, the imido ester being of the type where R1 and R: represent the same or diflerent aliphatic hydrocarbon radicals.

3. An anti-corrosion, emulsion-resistant turbine oil comprising a well refined mineral oil fraction containing about 0.001% to 0.1% of an oil-soluble imidic material prepared by reacting an aliphatic ester containing over about 20 atoms per molecule with ammonia at a temperature not less than about 40 C. and sufliciently high to yield an oil-soluble, normallyliquid fraction, separating said fraction from the normally solid products and recovering said fraction as said imidic material.

4. An anti-corrosion composition comprising a refined mineral oil fraction having a viscosity of at least about 150 seconds Saybolt Universal at 130 F. containing a minor proportion sufficient to impart anti-corrosion properties, of an oil-soluble imidic material prepared by reacting an aliphatic carboxylic acid ester containing at least about 20 carbon atoms per molecule with ammonia at a sufficiently elevated temperature to yield an oil-soluble fraction predominantly liquid at normal temperatures, and separating said oil-soluble fraction from the solid products of the reaction and recovering such oil-soluble fraction as said anti-corrosion imidic.

I 5. An anti-corrosion composition comprising a refined mineral oil fraction containing an anticorrosion agent in proportion suflicient to impart anti-corrosion properties, said agent being in the nature of an imido-ester having the probable structural formula:

where R1 and Rz'represent hydrocarbon groups providing a total of at least about twenty carbon atoms in the ester.

6. An anti-corrosion composition according to claim 5 wherein the ester contains an olefinic linkage.

7. An anti-corrosion composition according to claim 4 wherein the imidic contains an olefinic linkage.

8. An anti-corrosion composition according to claim 2 wherein the imido-ester contains an olefinic linkage.

9. A refined mineral oil fraction containing a minor proportion suflicient to impart anti-corrosion characteristics of an imidic material prepared by reacting an ester of an aliphatic carboxylic acid, which acid has at least about ten carbon atoms per molecule, with an excess of ammonia at a temperature of between about 40 C. and 400 C. and under superatmospheric pressure to yield oilsoluble normally liquid imidic fractions, separating such oil-soluble imidic fractions from the normally solid products of reaction and recovering such oil-soluble fractions as the anti-corrosion agent.

10. A refined mineral oil containing a minor but effective proportion of an amidine anti-corrosion agent prepared by reacting fatty acid amides with ammonia at elevated temperatures between about 100 F. and 500 F. and at super tmospheric pressure to produce normally liquid amidines of the probable formula:

and separating the liquid amidines from solid materials present.

11. A refined mineral oil containing a minor but effective proportion of an anti-corrosion agent prepared by reacting a fatty acid amide containing at least about 10 carbon atoms per molecule with a fatty acid chloride at elevated temperatures to yield a normally liquid oil-soluble imide fraction, separating the oil-soluble fraction from solid reaction products and recovering said normally liquid fraction as the anti-corrosion agent.

12. A refined mineral oil fraction containing a minor but effective proportion of an anti-corrosion agent produced by reacting ammonia with fatty acids and fatty acid esters containing at least consisting of imido esters and imides free from amides and other oil-insoluble ammonium derivatives, where the imido esters and imides have rewhere R1 and R2 represent the same or different spectively the following general f r l alkvl radicals, the whole molecule containing at least 20 carbons.

IJ 14. A composition according to claim 13 where- 5 in the added oil-soluble material is present in the and order of about 0.001% to 0.1%.

R1-C=0 PAUL W. FISCHER.

1 VANCE N.- JENKINS. Iii-( 3:0

CERTIFICATE 0E CORRECTION. Patent No. 2,388,152. .October 50, 19L

PAULW. FISCHER, ET AL.

It is hereby certified that error appears in the printed specification I of the above numbered patent requiring correction as follows: Page 1;, first column, line 1 claim 1., for "oil-soluble" read --oi1-ine:o1ub1e-; and that the said Letters Patent ehouid be read with this correction therein that the same may conform to the record of the case in thePatent Office.

Signed and sealed .this 5th day of Feb'ruary, A. D. 191%.

Leslie Frazer" (Seal) First Assistant Commissioner of Patents. 

